In the compressor and turbine sections of gas turbine engines, blades rotate about the axis of the engine. The blade tips come in proximity to the inner wall of the engine case, sometimes rubbing the case wall. To prevent excessive wear of the blade tip, abradable seals are sometimes attached to the internal case wall surface, so that when such rubbing does occur, the seals will wear away rather than the blade tips.
To extend the life of blade tips which rub against abradable seals in the turbine section of the engine, abrasive layers are sometimes provided on the blade tip surface. See, for example, U.S. Pat. No. 4,802,828 to Rutz et al., and the patents referenced therein. Rutz mentions several techniques for providing the abrasive layer onto the blade tip, including powder metallurgy techniques, plasma spray techniques, and electroplating techniques. The substrate to which the abrasive layers of the type described by Rutz are high strength superalloys, such as those based upon nickel and cobalt. The thickness of such layers is generally in the range of about 0.4 to about 2.5 millimeters.
The gas turbine engine industry has recognized the usefulness of the aforementioned types of abrasive layers in the turbine section, and now seeks to apply this technology to components used in other sections of the engine. The compressor section is one such section, and new techniques for applying abrasive layers to compressor components are required. This invention describes one such method.